Proceedings of the
Regional Flood Early Warning System Workshop
23-27 November 2015, Bangkok
CONTENTS
ACKNOWLEDGMENTS iii
EXECUTIVE SUMMARY iv
INTRODUCTION 1
OPENING SESSION 3
PRESENTATION SUMMARIES 4
1. SESSION 1: FLOOD FORECASTING AND WARNING SYSTEMS IN SAR 4
COUNTRIES
1.1 Flood Forecasting and Warning Services in Bangladesh 4
1.2 Status of Flood Forecasting and Warning in Bhutan 5
1.3 Flood Forecasting and Warning System in India 7
1.4 Flood EWS Activities in Nepal 8
2. END-TO-END FLOOD FORECASTING AND WARNING SYSTEM 10
2.1 End-to-End Flood Forecasting and Warning: Key Features and Requirements 10
2.2 Numerical Weather Prediction for Flood Forecasting 11
2.3 Data Requirements for Hydrological Modeling 11
2.4 Introduction to Hydrological Modeling 12
2.5 Decision Support Systems 14
2.6 Dissemination and Communication Aspects of Flood Early Warning Systems 15
2.7 Early Warning Dissemination: Bangladesh Experience 16
2.8 Preparedness and Response Systems 17
2.9 Feedback System 19
2.10 Community Feedback on Flood Early Warning 21
2.11 Capacity Building for End-to-End Long-Lead Flood Forecasting and 22
Warning – Bangladesh Experience
3. FLOOD FORECASTING AND WARNING IN SAR: ONGOING EFFORTS 24
3.1 Flood Outlook System for the Himalayan Basins 24
3.2 SAWI Program on Regional Flood Forecasting 25
3.3 Flood Forecasting and Warning Initiatives in Nepal and Myanmar 26
4. SPECIAL SESSION 28
4.1 Surface Water Level Monitoring via Satellite Radar Altimetry 28
4.2 Preliminary Altimetric Observation of the Ganges and Brahmaputra Rivers 28
4.3 WRF-Hydro: An operational large-scale real-time flood forecasting system 30
4.4 Rating Curves: Potential and predictability 31
4.5 Upstream Satellite-Derived Flow Signals for River Discharge Prediction 31
4.6 Operational Flood Forecasting for Bangladesh using ECMWF Ensembles 32
4.7 Rain Gauge Site Selection Tool 33
4.8 Flood and Water Level Prediction: Japan 33
4.9 Real-Time Flood Forecasting System for Bhakra Beas Management Board – 34
India Case Study
4.10 Quality Control of India River Level Gauge Data 35
4.11 Integrated Flood Risk Assessment: A case study of the Day River diversion 36
area in the Red River Delta, Vietnam
4.12 Present and Future Water Data in India 37
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EXPOSURE VISITS 38
EXPLORING POSSIBILITIES FOR A REGIONAL PROGRAM ON END-TO- 40
END FLOOD FORECASTING AND WARNING
CONCLUSION AND WAY FORWARD 43
ANNEXES
1. Agenda 44
2. Participant List 49
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ACKNOWLEDGMENTS
This report provides a record of the Regional Flood Early Warning System Workshop, held from 23-
27 November 2015 in Bangkok, Thailand.
The workshop was funded by the South Asia Water Initiative (SAWI), a multi-donor trust fund
managed by the World Bank. Established in 2009, SAWI’s strategic program aims for sustainable,
fair and inclusive development and climate resilience through increased regional cooperation on
transboundary river management in the South Asian Region.
The workshop was organized by the Regional Integrated Multi-Hazard Early Warning System
(RIMES), an international and intergovernmental institution that is owned and managed by its
Member States for building capacities in the generation and application of user-relevant early warning
information. The workshop brought together National Hydrological Services of four of its Member
and Collaborating States – Bangladesh, India, Bhutan, and Nepal – countries that share the
Brahmaputra, Ganges, and Meghna river basins.
RIMES would like to thank Dr. William Young, Lead Water Resources Management Specialist,
World Bank, and SAWI Program Manager, for his technical guidance to and invaluable support for
this workshop. RIMES also acknowledges Dr. Satya Priya’s valuable inputs to the design and
conduct of the workshop.
RIMES also thanks the International Centre for Integrated Mountain Development (ICIMOD),
University Corporation for Atmospheric Research (UCAR), Japan International Cooperation Agency
(JICA), and Asian Institute of Technology (AIT) for facilitating technical sessions that updated
participants on ongoing initiatives and new and emerging technologies in flood forecasting and
warning.
RIMES is grateful for ESCAP’s commitment to carry forward the outcomes of this workshop through
a Panel on Transboundary Flood Management for South Asian Region, under its proposed
Intergovernmental Panel on Transboundary Flood Management, and implementation of the action
plan adopted in this workshop through ESCAP and RIMES regional cooperation mechanisms.
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EXECUTIVE SUMMARY
South Asia is home to major transboundary river basin systems, such as the Ganges-Brahmaputra-
Meghna. The region is also home to 40% of the world’s poor, of which two-thirds live in the Ganges
and Brahmaputra basins. These river systems support livelihoods of millions of people. The Ganges
basin alone supports about 655 million people, of which 30% are very poor. Recurring floods in these
river basins have been a major development concern. With changing climate, floods are becoming
more frequent, more intense, and less predictable.
Despite occurrence of recurring floods, these river basins have very high population concentrations
due to livelihood opportunities that they offer. Relocation of communities away from flood zones,
thus, becomes an impractical option. Hence, flood forecasting and early warning, proven to be an
efficient and cost-effective alternate instrument for minimizing negative impacts and maximizing
potential benefits of flood, is essential.
Countries in the region have differential capacities in flood forecasting and warning. For a region
where flooding is transboundary in nature, development of an operational flood forecasting and
warning system would require a basin approach. The Regional Flood Early Warning System
Workshop, organized jointly by the World Bank (South Asia Office, New Delhi) and Regional
Integrated Multi-Hazard Early Warning System (RIMES) from 23-27 November 2015 in Bangkok,
brought together professionals and heads of flood warning institutions of Bangladesh, Bhutan, India,
and Nepal to explore possibilities for strengthening regional cooperation on transboundary flood
forecasting and early warning.
Participants to the 5-day workshop appreciated the cost-effectiveness and socio-economic value of
regional cooperation on transboundary flood forecasting and early warning, by adopting a basin
approach through sharing of monitoring, forecasting, and warning information. Participants
considered the potential value of undertaking basin-wide joint efforts to apply the best of weather/
flood forecast/ observation technologies to enhance forecast/warning lead times to up to 10 days, as
demonstrated in Bangladesh. Participants envisioned that transboundary flood forecasting and early
warning collaboration could be an entry point in building trust among participating countries. Such
collaboration could be gradually enlarged to cover broader flood management issues.
Despite inherent advantages, participants flagged challenges in putting in place a joint monitoring,
forecasting, and warning program due to differing perceptions of risk: upstream countries (Nepal and
Bhutan) considered flash floods as more important than riverine floods, while downstream countries
(India and Bangladesh) considered riverine floods as more important than flash floods. Differing
technical and institutional capacities and data sharing policies/collaboration frameworks (though some
bilateral technical arrangements exist) were listed as obstacles for putting in place a transboundary
flood early warning system.
To overcome these challenges, participants recommended making use of available regional
mechanisms by adopting three distinct, but integrated, approaches:
o Integration of flash flood (as most of flash flood subsystems contribute to basin-scale
floods) and riverine flood concerns at the basin level for promoting investment in
observation/monitoring and for forecasting purposes
o Building of flood early warning capacities to use emerging new-generation flood forecasting
technologies and incorporate these into flood risk information user systems
o Use of existing regional mechanisms for capacity building and regional sharing of
information/knowledge through institutionalized biannual meetings of senior and middle
level professionals
In the above context, it is important to highlight that the United Nations Economic and Social
Commission for Asia and the Pacific (ESCAP), a multi-sectoral intergovernmental platform in the
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region, has been mandated in May 2015 by its Member Countries, including those from the South
Asian region, through Resolution 71/12, to strengthen regional cooperation for flood forecasting in
transboundary river basins. ESCAP promotes intergovernmental, multi-stakeholder cooperation, such
as the Mekong River Commission, ESCAP-WMO Panel of Tropical Cyclones, and Typhoon
Committee, which bring together stakeholders that share risks across common river and ocean basins.
ESCAP’s multi-donor Trust Fund supported the establishment of RIMES, which provides technical
support for building national capacities for enhanced flood warning systems, and for pilot testing
new-generation forecast technologies for community-level application in the South Asian region.
RIMES also provides continued backup support to countries to ensure that: a) flood forecast
technologies are integrated into national systems and sustained, and b) biannual Monsoon Forums,
which bring together early warning information provider and user institutions in a dialogue and
provide continuous feedback on forecast technologies and risk communication practices, are
institutionalized.
Mandated by the Resolution, ESCAP committed to carry forward this World Bank-supported
initiative by establishing a Panel on Transboundary Flood Management for South Asian Region, with
RIMES serving as technical secretariat. This is in line with ESCAP’s proposal for an
Intergovernmental Panel on Transboundary Flood Management that includes key stakeholders –
hydrologists, meteorologists, and disaster management authorities – from riparian countries of
common river basins. The action plan, as adopted in the workshop, will be implemented through
ESCAP and RIMES regional cooperation mechanisms.
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INTRODUCTION
Background
The South and Southeast Asian regions are home to big river systems, such as the Ganges-
Brahmaputra-Meghna, Indus, Ayeyarwady, Mekong, etc. These river systems provide livelihoods to
millions of people in the region. During summer monsoon season, these rivers and their tributaries
frequently overtop their banks and create havoc due to flooding. Floods cause loss of lives,
livelihoods, and infrastructure; damage the environment, and hinder the development process. With
changing climate, floods are becoming more frequent, more intense, and less predictable.
Flood forecasting and early warning has been proven to be efficient and cost effective instrument for
minimizing negative impacts of flood and maximizing its potential benefits. To respond to user
demands, efforts have been considerable in transforming conventional real-time meteorological and
hydrological observation-based flood warning systems into weather forecast-based flood forecasting
and warning systems to enhance flood warning lead time, for saving lives and preserving livelihood
assets.
In the South Asian region (SAR), countries have differential capacities in flood forecasting and
warning. Many have basic infrastructure on hydrological and meteorological monitoring, based on
manual observation and conventional data transmission by telephone, VHF radio, and ordinary mail.
Customized numerical weather prediction for hydrological forecasting is still lacking. Hence, weather
forecasts are not integrated into hydrological models. Customized hydrologic and hydraulic models
are not yet available. Warnings are issued based on real-time monitoring, which provide few hours of
lead time only. Mechanisms to disseminate warning messages at the community level for taking
proper preparedness and immediate response measures are either lacking or weak. In most of the
countries in the region, flood warning system is not fully operational.
Development of an operational flood forecasting and warning system in the region requires a basin
approach, since flooding phenomenon in the region is trans-boundary in nature. For example, the
Ganges and Brahmaputra basins are contiguous, and encompass Nepal, Bhutan, India, and
Bangladesh. For an initiative that involves a number of countries, it is important to bring these
countries on board to facilitate such undertaking.
Objectives
The Regional Flood Early Warning System Workshop, organized from 23-27 November 2015 in
Bangkok, Thailand, is such initiative that brought professionals and heads of flood warning
institutions in SAR countries together to strengthen regional cooperation on trans-boundary flood
forecasting and early warning. Specifically, the workshop:
a) Took stock of existing flood forecasting and warning efforts in SAR countries;
b) Featured technologies and experiences from other countries/ regions;
c) Introduced operational personnel to new modeling tools;
d) Introduced the elements and requirements of an operational basin-based long-lead flood
forecasting and warning system; and
e) Explored possibilities of evolving a program for end-to-end basin-based long-lead flood
forecasting and warning system in the South Asian Region.
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The workshop had two parts:
a) Training workshop for senior/mid-level professionals, which involved lectures, interactive
discussions, participant presentations, group exercise and presentation, and exposure visits
to national meteorological and hydrological institutions in Thailand. Resource persons
came from University Corporation for Atmospheric Research (UCAR), AIT, International
Centre for Integrated Mountain Development (ICIMOD), Bangladesh, and the Regional
Integrated Multi-Hazard Early Warning System (RIMES).
b) Workshop involving heads and senior/mid-level professionals of the national hydrological
institutions/ national meteorological and hydrological services (NMHSs) for consideration
of a regional program on end-to-end basin-based long-lead flood forecasting and warning
system in the South Asian Region.
The workshop was held over five days, with the following program:
Day 1: Workshop introduction and contextualization; existing flood forecasting and warning
systems in SAR countries; introduction of end-to-end flood forecasting and warning
system, learning sessions on real-time observation and monitoring, numerical weather
prediction, data requirement for Hydrological modelling
Day 2: Introduction of basin-based long-lead flood forecasting and warning; ongoing
regional efforts; proposed regional program for SAR
Day 3: Special learning sessions on sources of hydrologic predictability and useful datasets,
followed by warning preparation, dissemination and communication, preparedness
and response, and feedback system; orientation on exposure visits
Day 4: Exposure visits to Thai Meteorological Department (TMD) and Royal Irrigation
Department (RID); debriefing
Day 5: Learning sessions on flood preparedness and response, and feedback system, followed
by developing an action plan for end-to-end basin based long lead flood forecasting
and warning system in SAR.
Annex 1 provides the detailed workshop program, while Annex 2 provides the participant list.
2
OPENING SESSION
Welcome Remarks. A.R. Subbiah, RIMES, welcomed all workshop participants.
He noted the increasing incidence of transboundary hazards, particularly in the South Asian region,
and emphasized the need for regional cooperation to reduce loss of lives and livelihoods.
Improvements in numerical weather prediction (NWP) techniques and integration of NWP outputs
into flood forecasting offer opportunities for enhancing flood forecast lead times. Thus, the workshop
shall explore a regional mechanism for integrating emerging/new technologies for improved flood
forecasting, particularly for transboundary rivers. Towards this end, Mr. Subbiah wished all
participants fruitful discussions.
Opening Remarks. Satya Priya, World Bank, provided the context of the workshop.
The Ganges-Brahmaputra-Meghna basin is an important region as it is one of the most flood-prone
basins in the world, affecting more than 18 million in the Ganges alone. The basin has the largest
number of the world’s poor. Climate change impacts further add to existing vulnerabilities.
Countries in the region have differing flood forecasting capacities. Data availability is a common
challenge. It is important to understand the full nuances of flood forecasting, from regional to
national, to local levels. The workshop, hence, shall take stock of available capacity, determine
existing gaps, and identify suitable measures to address these gaps. The workshop is also a good
platform to share and learn from each other’s experiences.
Remarks. Sanjay Srivastava, ESCAP, shared relevant ESCAP initiatives, particularly the promotion
of regional cooperation on transboundary river basins in the Asia-Pacific region.
The recent session of the ESCAP Commission gave ESCAP the mandate to work with Member States
on flood forecasting, from data exchange to integration of advances in science and sharing of best
practices. ESCAP promotes inter-governmental, multi-stakeholder cooperation, such as the Mekong
River Commission, ESCAP-WMO Panel of Tropical Cyclones, and Typhoon Committee, which bring
together stakeholders that face common risk. ESCAP’s multi-donor Trust Fund has supported
Monsoon Forums, NMHS capacity building, and pilot projects that ensure that risk information
reaches communities at risk.
Left: workshop opening session; Right: workshop participants
3
PRESENTATION SUMMARIES
1. SESSION 1: FLOOD FORECASTING AND WARNING SYSTEMS IN SAR COUNTRIES
Country representatives presented an overview of existing flood forecasting and warning system in
respective country, the salient features of which are summarized below.
1.1 Flood Forecasting and Warning Services in Bangladesh
Md. Abdul Latif Miah and Md. Amirul Hussain, Bangladesh Water Development Board (BWDB),
Bangladesh, presented the country’s flood risk context and the evolution of, advances made in, and
priorities for further development of the country’s flood forecasting and warning system.
Bangladesh is the most flood vulnerable country in the region, with almost one-third of the country
flooded every year, resulting to annual economic losses of about 3% to 5% of the country’s GDP.
Severe floods occurred in 1998, 1988, and 2007. The country’s location, topography, and high
population density make it vulnerable to floods and other hydro-meteorological hazards. Flood
forecasting and warning complement the country’s extensive structural flood management measures.
Bangladesh has an operational flood warning system during the monsoon season. The country’s
hydrological and meteorological observation system is still basically conventional manual type.
BWDB maintains a network of 343 water level gauges, of which 37 are automated telemetric stations.
Manual stations are equipped with mobile phone, which enables immediate transfer of data through
SMS to the head office. Satellite images are also applied to monitor water level conditions upstream.
BWDB’s Flood Forecasting and Warning Centre (FFWC) issues 5-day deterministic flood forecast
for 52 locations, and 10-day probabilistic flood forecast for 38 locations. Satellite altimetry-based
flood forecasting technology has also been developed, providing lead times of up to 8 days for 13
locations. Flash flood forecasts, based on rainfall intensity-duration thresholds, are issued for 2
locations.
The 10-day flood forecast system is based on medium-range rainfall forecast from the European
Centre for Medium-Range Weather Forecasts (ECMWF) ensemble prediction system, satellite
precipitation data from the U.S. National Oceanic and Atmospheric Administration’s Climate
Prediction Center Morphing Technique (NOAA/CMORPH) and U.S. National Aeronautics and Space
Administration’s Global Precipitation Climatology Project (NASA/GPCP), rain gauge data from the
World Meteorological Organization’s Global Telecommunication System (WMO/GTS), and local
meteorological and hydrological data. River discharges are predicted at upstream boundary locations,
using data-based and distributed hydrological models. Forecast errors are minimized using simple
regression of model outputs against measured discharge. Discharge forecasts at boundary locations
are used in Mike 11 hydraulic model, to generate water level forecasts at 38 locations downstream of
the Brahmaputra, Ganges, and Meghna rivers (Figure 1.1).
Flood advisories are issued to the public by voice and text messages, phone, social media (Facebook),
FFWC website, and display boards installed at selected locations; by email to institutional users; and
by fax and hard copies to policymakers and top officials.
Disaster Management Committees and user communities in pilot locations have been trained to
respond to warning messages that are based on probabilistic forecasts. Actions are taken
corresponding to the level of flood threat. These include: stocking of seeds, delaying of planting,
early harvesting, increasing height of fish pond dykes, enclosing fish ponds with nets, raising
livelihood assets such as handlooms, increasing elevation of storage areas for goods, moving of
4
livestock to safe locations, temporary sealing of tube wells, stocking of emergency supplies (food,
fuel, medicine), and securing bamboo for building temporary bridge to connect houses to high land.
www.ffwc.gov.bd Flood Forecasting and
Flood Forecast points Warning Services
River% Sta